I. Field of the Disclosure
This disclosure relates generally to the control and operation of heating ventilation and air conditioning (HVAC) systems.
II. Description of the Related Art
The “background” description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description which may not otherwise qualify as prior art at the time of filing, are neither expressly or impliedly admitted as prior art against the present invention.
In a building, air within separate areas of the building is often maintained via separate heating ventilation and air conditioning (HVAC) units. Each HVAC unit supplies and exhausts the air from an area in the building. The supply air or make-up air is composed of fresh air drawn from outside the building and return air taken from within the area. The fresh air must be conditioned to provide the area with air at the correct temperature. For example, when the outside air temperature is colder than a desired air temperature, the fresh air must be heated. Conversely, when the outside air is warmer than the desired air temperature, the fresh air must be cooled. Conditioning the fresh air requires additional energy resulting in an increased cost of running the HVAC system. Therefore, to reduce the cost of operating the HVAC system, when a large temperature differential exists between the fresh air and the desired air, the HVAC system may decrease the ratio of fresh air to return air. By contrast, when there is a small temperature differential between the fresh air and the desired air, the HVAC system may take advantage of “free heating or cooling” and increase the ratio of fresh air to return air.